Ball-grinding machine.



0. W. SCHAUM.

BALL GRINDING MACHINE.

APPLICATION FILED MAY 26. 1911.

Patented Jan. 1, 1918.

SHEETQISHEET 0. w. SCHAUM.

BALL GRINDING MACHINE.

APPUCATION FILED MAY 26.1917- 1 ,366 Patented Jan. 1, 1918.

2 SHEETS-SHEET 2- F 020 F 0 v o Z] w W wfo'z alt 72k W my) 5 attozueu s rest upon spaced "against which th tating ball-revolving ring. 7

OTTO W. SCHAUM, 0F PHILADELPHIAfPENNSYLVANIL.

BALL-GRINDING MACHINE.

Specification of Letters Patent.

Patented Jan. 1, 1918.

Application filed May 26, 1917. Serial No. 171,280.

T 0 all whom it may concern Be it known that I, Orro W. SCHAUM, a citizen of the United'States, and a resident of Philadelphia. county of Philadelphia,

State of Pennsylvania, have invented new and useful Improvements in Ball-Grinding Machines, of w ich the following is a specification. v

The invention relates to machines for grinding balls and particularly. to machines in which the balls while being operated upon by an ab'rading "wheel are supported by or ballsupporting rings In machines ofthis type that portion of.

flthe ball which is to be operated upon is orced through the space between the ballsupporting rings by the ball-revolving ring vim and is acted u at will.

l by the abrading-wheel which is on the opposite side of the spaced supporting-rings from that upon which is located the ball-revolving ring or ball-press ingv ring as it is frequently called.

The machine which is the basis of the present invention is of the vertical type, to wit, of the type in which the ball-revolving ring and the abrading-wheel each revolves about its own vertically extending axis. In the machine shown the spaced ball-supporting rings are concentric with each other and one of these rings is frequently referred to as the outer ball-supporting or outer segment ring and the other of these rings is frequently referred to as the inner ball-supporting or inner segment ring.

In machines of this type it is desirable to have these segment rings firmly held in respect to each other and in the construction shown this is accomplished by supporting the inner segment ring on a carrier that can be secured to and is concentric with a carrier upon which the outer segment ring is located. ring can be moved vertically at will so as to raise and lower the inner segment ring. The ball-pressing ring is also secured to an intermediate carrier which is revolubly mounted on one of the segment ring carriers, preferably upon theinner segment ring carrier,

and the construction is such that the inter- "mediate carrier. can bc-raisedand lowered at will. The abrading-wheel is also mounted so that it can be readily raised and lowered s are pressed by a rochine. ,means for this purpose are well known in The carrier for the inner segmentground and to supply a new lot or charge of balls for a succeeding grinding.

The machine which is the basis of the present invention is constructed so that balls can be supplied thereto and removed therefrom in the manner just described, although it is; to'be understood that the invention is not necessarily limited to a machine in which the balls are supplied and removed in said manner, as there can be readily applied to the machine a means for successively feeding the balls into operative position through a feeding trough and a means for successively ejecting the balls being ground and'for delivering the same from the ma- A feeding means and an ejecting the art.

.The invention is directed to the features above referred to and to other features of construction, as will be hereinafter more clearly pointed out.

. As illustrating a specific manner in which the invention may be realized reference is made to the accompanying drawings forming apart of this specification and inwhich drawings,

. Figure l is a vertical view of a ball grinding machine partiallyin section.

, Figs. 2 to 6 inclusive illustrate the different positions the spaced-segment-rings, ballpressingt ring and the abrading-wheel may assume relative to each other; in other words, these views illustrate the position which the parts may occupy from the time when the lot of balls is placed on the machine until said lot has been discharged from the machine and another lot "substituted therefor fora succeeding grinding operation.

Figs. 7 and S are. respectively, plan and side views of a portion of the mechanism w iich is employed in the raising and lowering of the abrading-wheel.

The referencecharacter 1 designates the main frame of the machine which is a vertically extending frame. Acarrier 2 is connected "to or carriedby the upper end of I rings whereby lower end thereof and this carrier is frequently referred to asqthe outer carrier-since the outer segment ring is secured to-or carried by it. An inner ball-supporting, ring or segment ring 4' is concentric with the outer ring 3 but spaced therefrom and the rings 3 and 4-constitute the'spaced ball-supporting or segment rings. A ball-revolving ring, or ball-pressing ring 5 as it is frequently called, engages a when on the spaced segment rings and forces the balls against said segment rings so that a portion of each ball extends through the space the balls can. be engaged by the abrading-whecl 7 when in normal opertive'elevated position. The normal operative position of this wheel 7 is indicated in Figs. 2 and 6. The inner segment ring 4 is carried by. a spindle or shaft 8 by being secured to the lower end of the latter. This spindle or shaft 8 may be considered as a part of an inner carrier 9 the functionof which inner carrier is to firmly maintain the inner segment ring 4 in operative position in respect to the outer segment ring 3. The inner carrier- 9 may also be considered to comprise a bushingor sleeve 10"although in many. respects this bushing or sleeve 10 might be considered as an adjustable part of or on the oute'rcarrier 2, dependent upon the particular view taken. Upon the bushing 10 there is revolubly mounted'an intermediate carrier; 11 to which there is connected the ball-pressing ring 5 through the-medium of an annular ring 12 and bolts 13.- A resilient means'as' 14 may be provided between the underside of a flange 15 of the intermediate carrier and theahnularring 12 to which the. ball-pressing:-ring;:5r :is directly connected. A hand-operated. nut '16 is upon the exterior ofrthe bushingor sleeve 10 and a shoulder- 16. on'this nut engages or is engaged byla bearing member '17 and collar 18. -The collar 18 is secured to a hub carrier 11 and this hub is--re\'oli1bly'mounted on the bearing member 171 that's-on the sleeve or bushing 10. If the-bushing or sleeve 10 is considered as av part of the inner carrier 9,.as it may be, then the intermediate carrier 11 may be considered to be revolubly mountedon saicbiuner. carrier 9. 11f, however, the member 9 18 to be considered an ad ustable parhot or on theouter carr en 2 then the intermediate carrier 11:. might .be considered to be" revolubly mountedg u pon a central hollow portion ofthe-outer carrier. A shaft 20 is carried in bearings -21 and 22 that are on the outer carrier'2:and authclower end of this shaft 20 tlierenis sec ed .apinion 23 wlnch drives the I intermediate carrier -1l through the medium of a gear 24 row of balls 6-.

between said segment 'carrier' 2.

threaded messes I belting2'5 which engages the pulley 26 that is keyed to the shaft 20.

-It will therefore be seen that the intermediate carrier ll-and ball-pressing ring 5 secured thereto can be continuously rotated due to the driving arrangement thus der scribed, and the carrier ,can. be positioned as desired by means of the hand-operated nut or wheel 16 that is threaded on the eX- terior of the bushing or sleeve '10. A protecting guard 2 is on the outer carrier 2 and thisguard has a depending apron 2" which extends downwardly past the lower edge of the teeth, of the gear 24. The bushing or sleevedO can be positioned vertically, aswill hereinafter appear, by means of nuts .27 and 28. These nuts are shown as being screwed upon the exterior bushing or sleeve lO'and they have opposing tapering faces 27 and 28 which respectively engage the beveled faces 27 and 28" of the. outer Dueto this tapering .of the nuts the bushing or sleeve 10 can be readily secured in a fixed adjus'tedposition. bushing or sleeve extends downwardly whereby it can guide, press and support .the lower end of the spindle or shaft 8. 'The lower exterior portion of the spindle 8 has a tapering bevelel portion 29 which engages a beveled portion 30 at the lower end of the bushing or sleeve 10v and the upper end of the spindle or shaft 8 is threaded at 31 so as to receive a nut o'r hand-wheel 32. The nut or hand-wheel 32 has a tapered portion 33 which engages a beveled portion 34 at the upper end of the bushing o'r sleeve, and due to the construction just described This the spindle or shaft 8 can be firmly clamped "ring 4, as will hereinafter appear; However.

after each operation of "lowering the inner segment ring 4 it is'advisable'to have the segment. ring restored to'lexactly the position which it occupied during the previousgri nding'operation. In other words,.this inner segment ring 4 should not be rotated.

relatively to its companlon segment ring.

In order to assure the return of the segment ri g to the same osition which it previously-- been ground, it is advisable-to lowerturning the hand-Wheel 32 in one direction occupied there is provided guiding members,

to effect the lowering and by turning the hand-wheel 32 in the opposite direction to effect the raising. Of course the hand-wheel 32 must be turned tight enough so that in, the

elevated position the segment ring will he I secured in place.

The abrading-wheel 7 is carried on a head 36 that is keyed to the upper end of a: shaft 37 which is mounted in bearings 38 and 39 that are on a verticallymovable frameAO; This frame 40 is slidably mounted on a vertically extending guideway member 41 which 1s on the main frame l-and by vraising and lowering the movable frame 40 the abradingwheel 7 can be raised to operative position and subsequently moved from operative position. The bearings 38 and 39 are, of course,

constructed so as to properly take care of.

any radial thrust as Well as any longitudinal thrust resulting from the performing of the grinding operation. A counter-weight s2 is connected to the movable frame 40 by means of a cable or flexible connector 43 which passes over an idler-pulley 44: that is mounted on the main frame 1. A rack 45 is secured at 46 to the movable frame 40 and the upper end of thisrack is engaged by a pinion or segment member 47. This pinion or segment member 457 is mounted on a shaft 48 that is carried in suitable hearings on the main frame 1 and to this shaft there is keyed or otherwise secured a hand-lever 49 which canbe relied u on to effect a ouick raisin and lowering of the movable frame 40. This may be considered to constitute means for providing a rough orcoarse adjustment.

In the grinding of balls it is necessary that the abrading-wheel be positioned or feed with a nicety of adjustment and this is accomplished by adding to themechanism which comprises the pinion or segment 4:? and the shaft 48 a woruywheel 50 and worm til, the latter of which can be positioned by hand. The worm-wheel 50 is not directly connected to the shaft 48 but can be indirectly connected to said shaft by locking means 5:? for locking, when desired, the Worm-wheel 50 and the hand lever l so that they cannot move relatively to each other and so that they will move together. The worm 51 is carried on a shaft 53 which is mounted on a hearing 54 that i sedured to the main frame 1 and is operated by means of a handle 55 on the shaft 53. k a

The locking means 5:2 for in effect securing the worm-wheel 50 to the leveiylll comprises notched plate 56 which is directly com no /ed to thes s :Wheel A movable ees abradingwheel from operative position and ,loclrieg memher or latch 5 normallyextehds plate 56, beingzpressed into this position; by

The locking member of -latch 57 can he Y3" tracted whereby it will disengage the plate. re

56 by the operator forcing a handle 60 toward a handle 61 the latter of which is on the lever? It will therefore be seen that the l ver &9 can be relied upon to lowierthe 7 to restore the abradi ii-gewheel to practically its final position when the locking mecha nism 52 is rendered inoperative by causing the latch 57' to disengage the plate 56 When, however, the abrading-wheel 7 is practically in its normal position it can be fed or adjusted through thefmediuln of the Worm 51 and worm-wheel 50 provided the locking means is positioned whereby the worm-wheel 50 is locked to the lever 49, or in other words indirectly connected to the shaft.

It will be manifest that instead of making the entire frame 40 movable vertically the same end could be accomplished by constructing the shaft 37 so that it could move vertically relative toaframe in which'it is revolubly mounted. was such a construction counter-weighting means is preferably applied so as to lift or partially lift the shaft and the abrading-wheel thereby, and the adjusting mechanism should be con structed so as to be applied to -some vertically movable member which would control the position of the shaftyor which would ultimately control the position-of the abrading-\vheel. llroadly speaking the conhectionof the rack 45 to the frame may be considered as a connection made to some verthe position ofthe shaft 3'? and ahrading 11c Wheel carried by it. ()n the main frame 1 there is mounted a pair of idler-guide pulleys 61 one of whichdelivers a belt 62 in a certain definite or comparatively fixed position to a pulley 63 and the other of which receives the belt from said pulley 63. The pulley 63 has a cylindricalface keyed on the shaft 37 and is moving vertically relative. to the belt 62 which is delivered to the pulley in practically one position only. This belting serves to drive the abradingwvheel '5 'in anj' vertical. position in which it may be located, will be manifest from an inspection of Fig. 1. In this figure it will also be noted that the axis about which the tubular ahradirig wheel 7 revolves is eccentric or offset with respect to rheaxis of rotation of the hall-pressing: ring-the latter of which is con en r n'ith the bell seats of the spaced segment This arrangement of the 30 -I the machine and 6 tubular abrading wheel enables the operative face thereof. to be employedfor its full width. I The positions which 5 rings, the ball-pressing ring and the abrading-wheel 7 can assume relative to each other at different'times and for'ditferent purposes are illustrated in Figs. 2 to v6 inclusive. In each of these figures the outer segment ring is designated by 3, the inner segment ring by 4, the ball-pressing ring by 5. and the abrading-wheel by 7. In Fig 2, 6 indicates arow of balls which have been ground and are ready 'to be ejected or delivered from designates anew lotof balls which arearranged in a row prepara= tory to'being placed in the machine for grinding. In Fig. 3, the balls 6 and 6 are shown remaining in theposition which they occupy in Fig. 2 but the abrading-wheel 7 has been lowered preparatory to'lowering the inner segment ring' l whereby the row of balls 6;.will be delivered from the machine. l Vhen the abrading-wheel ,7 is in the position shown in Fig. 3 a pan P 'is placed on the top of the abrading-wheel in the space. between the abrading-wheel' and the segment rings and the inner. spaced segment wheel or nut 32 (see .Fig. 1)-so as to drop the inner segment ring 4, as in the position shown in Fig. 4:. This allows the balls 6 to drop into the pan P as is .indicated in 4: and thereafter the spaced segment ring 4 is raised'to the position shown in Fig. 5 and this is followed by a raising of the pressing ring 5 to the position'shown in Fig. 6.

- According to Fig. 5 the abrading-wheel 40 7isshown as being raised before the pressing-ring is raised, but manifestly the abrading-wheel 7 need not be raised until after the balls to be ground occupy the position Qof the balls shown in balls to be ground are resting upon the spaced segment rings v3 and 4 the ball-pressing ring 5 is moved downwardly so as to press the balls against the seats on said spaced segment rings and the abradingwheel 7 is placed in operative position relative to thespaced segment rings 3 and l, if not already in the desired position. Such adjustment as is required can be given the abrading-wheel 7 due to the worm and wormwheel construction heretofore described. r I p The grinding. operation can now proceed and continue until the balls 6 have been brought to size after which the cycle of operations above described can be repeated.

Therings 3 and 4 have been referred to as ball-supporting or ball segment rings. They have been referred to as segment rings because frequently in the manufacture of these. at rings it has been found advisable to have the spaced segment I ring is not to be construed as limit ng these ring 4: is loweredby turning the handcall conveyin e u b Fig. 2. Then the the wearing portions thereof made of segments of hardened steel secured to the larger rings carrying the same. It is to be understood, however, that the expression segment ball-supporting. rings to a construction in which segments are necessarily-employed to provide the raceways for the balls. It is quite important that these segment rings be properly positioned relative to each otherand in order to provide for .any inequalities or inaccuracies, due to workmanship, warping of the metals, or otherwise, a dutchman iconstruction is provided at 3 between the segment ring 3 and the carrier therefor and atl between the inner segment ring 4 and the carrier therefor. I

In the machine shown no means for automatically feeding balls to the grinding space is shown and no means for automatically as delivering the balls from-the grinding space is shown. --I t is not difiicult, however, to provide a construction for this purpose and the invention herein described is applicable to a machine in which there are employed means for automatically feeding, and for automatically discharging balls from the machine whereby the grinding operation may be continued; in other words, in which balls can be fed into the machine-during the grinding operation while simultaneously therewith other balls are being conveyed from the machine. Apparatus for automatiballs to and from the ball. grinding machines in the manner just referred to is old and well known'in the art.' The means which comprises the adjustable bushing orsleeve 10 canbe employed as a means .for effecting a fine or nice adjustment so that should for any reason the spindle or shaft 8. be moved relatively thereto the latter can be properly positioned by merely turning a nut when it is desired to restore the shaft 8 to its normal position.- This construction has its advantage even in a machine where the feeding is continuous as well as in a machine which is operated as. for example, by the-method illustrated in Figs. 2 to 0 inclusive. The vertical movement of the movable frame 40 is also useful where the feeding is continuous in that it 'allows abrading-wheels of different depths to be employed and allows of the employment of prz'wtically the full depth of an abrading-wheel. v The improvements herein set: forth are a not limited to the precise construction and arrangement shown for they may be embodied in various'forms and modifications without departing from the spirit and scope of the invention.

\Vhat I claim and desire to secure by Letters Patent of the United States is 1.- A machine of the class described com prising in combination a main framesup:

. which .is arranged .with, said spindle or shaft having at the i curely clam slidably mounted on by the abrading-wheelcan be raised sleeve and having secured to .the lower end thereof an inner segment ring which is spaced from said outer segment ring and so as to cooperate therelower portion thereof a beveled face which engages the tapering face at the lower end of the sleeve and a nut on the upper end of said shaft which nut has a tapering face that engages thetapering face at the upper end of said sleeve whereby said nut can sesaid spindle or shaft in a fixed position in said sleeve or bushing, an intermediate carrier said sleeve or bushing and anut engaging the exterior of said sleeve'or bushing for positioning the carrier along said sleeve or bushing, .a ball-pressing-ring-connected to said intermediate carrier, a tubular abrading-wheel located below said spaced segment rings and carried on a shaft which is in bearings that are on a frame which is the main frame whereand lowered relatively to the outer spaced segment ring, means comprising a counterweight for counter-balancing said movable frame and parts carried thereby, and means for effecting a raising and lowering of said movable frame and for in adjusted position. t. v I

7. A machine ofthe class described comprising in combination a main frame supporting thereupon an outer carrier, an outer segment ring secured to said carrier, an 1nporting rings and a ball-pressing ner carrier adjustably mounted on said outer carrier, means for securing carrier in adjusted position on said outer carrier, said inner carrier, a ball pressing rlng, an intermediate carrier to which said ball pressing ring is connected, which intermediate carrier is revolubly mounted on said inner carrier and is adjustable along said inner carrier, and a rotatable abrading-wheel arranged to engage balls when the latter are in operative position on said segment rings. 8. A machine of the class described comprising in combination an upright main frame, an outer carrier supporting at its lower. end a ball supporting or. segment "lan'inner carrier comprising a bushing ljee've}; which can be adjnstably posioned in the outer carrier. means for clamp- '55.

ing said bushing or sleeve to said outer 'carrier, a vertically adjustable spindle or shaft extending into said bushing or sleeve, means for clamping said spindle or shaft to said bushing or sleeve, an inner ball supporting or segment ring secured to the lower end of said spindle, an intermediate carrier rerolubly mounted on said bushing'or sleeve, a

ball pressing ring connected to said intermee diate carrier and'arranged to press downwardly upon balls supported by or on said revolubly mounted uponholding said frame said inner.

an inner segment ring secured tocounter-balancing and worm-wheel segment rings, which last mentioned'finfi have spaces'between' them through which theballs extend when thus pressed, and a revoluble abrading-wheel arranged to engage theballs thus pressed.

9.'A ball grinding machine of the class described comprising in/combination spaced segment or ball-sup o rting rings which. are.

relatively stationary when a grinding opera.- tion is being per formed but 'which are mounted so that one of the segment rings can be moved vertically relative to its companion ring, a ball-revolving ring arranged to press balls downwardly on the seats of saidsegment rings during a grinding opera a fixed but rotatable'shaft, a pinion or gear'ao I,

secured-to said shaft and engaging said rack, a worm-wheel revolubly-mounted on said shaft and a' hand-operated worm for turning said worm-wheel, a lever secured to said shaft for turning it, and means for -mounted,on a shaft having a vertically extending axis and so that the abrading-wheel can be raised and lowered, means for the weight of the abrading-wheel and the vertically movable parts upon which the same is supported. and -a rack connected to one of the vertically mov-' able parts which rack is actuated through the medium of a gear carried on a shaft which is mounted in the main frame, said shaft having associated therewith a worm for effecting a fine adjustment and a hand-operated lever for-effecting a coarse adjustment.

11. A machine of the class described comprising in combination spaced segment rings, a ball-pressing ring located at one side of said spaced segment rings. an abrading-wheel located at the other side of said spaced segment rings. means comprising one set of members for effecting a fine adjustment of the abrading-wheel relative to the spaced segment rings 'and'another set of locking the'worm-wheel tothelever when "desired.

10. A machine of the class described. com

of the abrznling-wheel relative to said ball segment rings.

12. A machine of the class described comprising in combination spaced segment rings, a ball-pressing ring above said spaced segment rings, an abrading-wheel below said spaced segment rings, means forcausingone of the spaced segment rings to be moved downwardly relative to the other spaced-f segment ring and for securing said ,vertically movable spaced segment ring in an elevated operative positlon, and means for raising and lowering said abradingwheel,

said last-mentioned means comprising members for effecting a quick raising and lowermg of the abrading-wheel to and from operative position and also comprising members for effecting a Qow fineadpistment when the abrading-wheel is in operative position. F

13. A machine offtlre class described comprising in combination spaced segment rings, at least one of which is vertically movable relativerto the other, a vertically movable ball-revolving ring for pressing balls downwardly against seats on said spaced segment rings when the latter are in operativeposition relative to each other, a vertically movable abrading-wheel located below said spaced segment rings, and means for raising and lowering said abrading? wheel said means comprising'members one of which is a hand-operated lever for efiecting an extended, quick, vertical movement of the abradmg-wheel, said means also comprising a worm-wheel and hand-operated worm for effecting a slow, fine adjustment.

14. A machine of the class described comprising in combination spaced segment rings, at least one of which is vertically movable relative to the other, a vertically movable ball-revolving ring for pressing balls downwardly against seats on said spaced segment ringswhen the latter are in operative position relative to each other, a

vertically movable abrading-wheel located below said spaced segment rings, means for raising and lowermg said abradmg-wheel said means comprising members one of I which is a handoperate'd lever for effecting an extended,iquick, vertical movement ofthe abrading-wheel, said means also comprismg a worm-wheel and hand-operated -worm for effecting a slow, fine adjustment,

and a weight arranged to counter-balance at least apart of the weight of the abradingwheel and the movable parts carrying the same.

15. A machine of the class described comprising in combination a main frame, spacedinner and outer segment rings, carriers for said spaced segmentrings, which carriers are supported by said frame. a ball-pressing ring and rotatable carrier therefor, means rotating said last-mentioned carrier, an abra'ding-wheel arranged to cooperate with said spaced segment rings and said ballpressing, a vertically movable shaft carrying a verticallyhiovablepulley secured to said shaft, sauna .gtraveling in a fixed path, the constr uct'on ---heing such that the pulley can be moved vertically relative to that portion of the belting which engages the same.

16.. A machine of the class described comprising in combination an upright main frame carrying at the upper end thereof an :outer carrier supporting at the lower end thereof an outer ball-supporting or segment ring? an inner carrier supporting at the lower end thereoi an inner ball-supporting segment ring which is spaced from the outer ball-sup'portingor segment-ring, an intermediate revoluble carrier mounted on one of the segment ring carriers, and means engaging one of said segment ring carriers for positioning sa d intermediate carrier, a hall pressing ring connected to said intermediate carrier, an abrading-wheel located below said segment rings, a frame slidably mounted on a vertically extending guideway on the main frame a shaft mounted inbearings in said movable frame and earryin the abrading-wheel at the upper end or the shaft, and means carriedby said mainframe and secured to said movable frame for effecting adjustment of the latter.

17 A ball grinding machine of the class described comprising in combination a ver tically extending main frame, an outer earrier on said mainframe, an outer segment ring secured to said carrier, a bushing or sleeve passing through a vertically extending opening in said carrier and held in. place by a pair of opposing nuts on the sleeve, a

spindle or shaft extending through said. vbushing or sleeve and having secured to the lower end thereof an inner segmentring which is spaced from said outer segment ring and which inner segment ring is an ranged so as to coii'perate with the outer segment ring, said spindle or shaft having at the lower portion thereof a face which engages the lower end of the sleeve, a nut on the upper end of said shaft, which nut has a face that engages the upper end of said sleeve whereby said nut can securely clamp said spindle or shaftin a fixed posi tion in said sleeve or bushing, an intermediate carrier revolubly mounted upon said sleeve or bushing, a nut engaging the eX-' terior of said sleeve or bushing for posicarrying a segment rin shaft is carried by said ushing or sleeve, a

which spindle or second carrier carried by'said bushing or sleeve, which second carrier has secured to it a ball ring, means between said second carrier and said sleeve whereby said second carrier can be positioned along said bushing or sleeve','and an abrading-wheel operatively associated with said rings.

' 19. A machine of the class described comprising in combination 'a frame, a bushing --:,01' sleeve, means for maintaining the bush- 'lng or sleeve in pos1t1on on the frame, a

spindle or shaft extending into said bushing or sleeve, a segment ring carried by said spindle or shaft, a second carrier, which second carrier is revolubly mounted on said bushing 01' sleeve, means between said. second carrier and said bushing 01 sleeve for.

positioning the second carrier along said bushing or sleeve, a ball ring secured to said second carrier and an abrading-Wheel operatively associated with said rings.

This specification signed and witnessed this 24th day. of May, A. D. 1917,

OTTO -W. SCI-IAUM.

Signed in. the presence of- B. G. ELLIOTT, WM. H. HICKS. 

